However, "our findings suggest that making medication changes during this period is not beneficial," said Anderson, who is a primary care research fellow at the University of California, San Francisco (UCSF).

"Instead, deferring medication adjustments ... [until after] patients are recovered from their acute illness is likely to be a safer course," he said in a university news release.

In the study, the researchers looked at more than 4,000 patients, aged 65 and older, with high blood pressure who were hospitalized for non-cardiac conditions that typically don't require an increase in blood pressure meds.

Half of the patients had their blood pressure medications increased when they left the hospital and half did not.

A year after discharge, those who received increased blood pressure medications did not have improved blood pressure control or a lower risk of heart problems, compared to those who didn't have their blood pressure medications increased, the findings showed.

But within 30 days after discharge, the patients who received increased blood pressure medications were more likely to have been readmitted to the hospital (21.4 percent versus 17.7 percent) and to have had serious medication-related problems, such as falls, fainting and kidney injury (4.5 percent versus 3.1 percent).

Anderson stressed that the new findings do not apply to patients hospitalized for heart conditions, and they may also not apply to younger or healthier patients.

"The goal of starting patients on new blood pressure medications is to reduce their long-term risk of heart attacks, heart failure and strokes, but our finding suggests the right time to start these medications is not when patients are hospitalized for other conditions," he said in the news release.

Two experts in cardiovascular care who weren't involved in the study agreed with the findings.

"The key to this study was the focus on patients admitted to the hospital for non-cardiac conditions," said Dr. Satjit Bhusri, a cardiologist at Lenox Hill Hospital in New York City. "In such cases, an elevated blood pressure response is common as it is a physiologic response to stress, trauma or inflammation."

Piling on added blood pressure-lowering treatments amid these "acute" but temporary hikes in blood pressure "has no benefit," he believes, and "in fact, may cause harm."

Dr. Guy Mintz directs cardiovascular health at Northwell Health's Sandra Atlas Bass Heart Hospital in Manhasset, N.Y. He said that, for older patients hospitalized with non-cardiac conditions, "the message of the study is clear and rings true that unless blood pressure is dangerously high, no adjustment [in blood pressure medication] should be considered."

Instead, doctors "can safely discharge the patients on their standard therapy and arrange for outpatient follow-up with their usual physicians," Mintz said.